Hints of cosmic ray-climate link in sediment core from Japan

But the correlation only holds during some of the times examined.

The idea that galactic cosmic rays play a large role in Earth’s climate may, at first blush, sound like a 1950s sci-fi premise, but it continues to capture attention. Some of that attention comes from folks desperate to find a climate control knob that makes anthropogenic greenhouse gas emissions seem insignificant, but some comes from researchers curious to test the hypothesis.

That hypothesis states that cosmic rays (high energy charged particles that enter our solar system) facilitate the nucleation of cloud droplets when they hit Earth’s atmosphere. If the incoming flux of cosmic rays increases, so too does cloud cover. Since clouds reflect sunlight back into space, more of them should mean a cooler climate (although that depends in part on the clouds' altitude). The solar wind shields the Earth from cosmic rays, greatly reducing the number that make it through, so the incoming flux ebbs and flows with solar activity.

There are, however, many issues with the idea. Cloud cover is also controlled by global temperature in important ways. An ongoing experiment at CERN has shown that charged particles can induce the formation of tiny atmospheric particles, but it doesn't necessarily follow that those particles can grow to the size of cloud condensation nuclei and influence the number of cloud droplets. And while some correlations between cosmic rays and global temperature in recent history looked pretty strong, notable exceptions have cast doubt on a causal connection.

Researchers have tried to test the hypothesis by finding natural experiments in the climate records. Unfortunately, those can be difficult to interpret, since solar activity can influence both cosmic rays and the amount of sunlight Earth receives. Since the Earth’s magnetic field also fends off some cosmic rays, variations in magnetic field strength are attractive tests because they aren't connected to solar activity in any way.

One such study looked at a marked weakening of Earth’s magnetic field about 41,000 years ago called the “Laschamp event”. Though the magnetic field was about 90% weaker, no climate response is seen in ice core records.

Climate records in the mud of Osaka Bay

A recent paper tries again with a similar strategy. Using a unique sediment core from Osaka Bay in Japan that goes back three million years, the researchers compare five interglacial periods 680,000 to 1.08 million years ago. During two of them, longer-lived magnetic pole reversals occurred that included several thousand years of a very weak magnetic field. Because the climate was warmer at these times than during the Laschamp event, the researchers hoped that any cooling signal resulting from the increase cosmic ray flux would stand out more clearly.

The sediment core is much different from the usual ocean sediment core climate records, which normally use measurements of oxygen isotopes in the shells of single-celled foraminifera. In the Osaka Bay core, temperature has to be inferred using the species of plant pollen and diatom plankton that are present.

The link between these species and climate comes via sea levels. Because of an underwater ridge at the mouth of Osaka bay, the area is shaped a bit like a bathtub. When sea level is low, the river feeding the bay makes it a freshwater body; when sea level rises above the ridge, the bay becomes salty. This transition can be seen in the chemistry of the sediment as well as the diatom species living at the time.

In comparing the five interglacial periods, the two that coincided with magnetic pole reversals did appear different from the others. While the peak in reconstructed temperature and sea level lined up during the other three interglacials, the warmest temperatures appeared to lag behind the highest sea level by several thousand years during the magnetic pole reversals.

Because the increase in cosmic rays would be greatest near the equator, and minimal at the poles, the researchers interpret this as the regional climate being cooled by increased cloudiness, even as the ice sheets are melting back and raising sea level. The researchers suggest that this could be why the climatic effects of cosmic rays aren’t seen in ice core records.

Zooming in on those two interglacials, the researchers looked to see how closely changes in reconstructed temperature tracked magnetic field strength (based on magnetic measurements of the core). There appeared to be a tantalizing correlation over some periods, but a disconnect during others.

Problems and weak correlations

While this adds a couple more intriguing (if partial) correlations to the stack, we still lack a mechanism that clearly links cosmic rays to cloud formation. And several components of the study’s results are less than satisfying.

Raimund Muscheler, a researcher at Lund University in Sweden who has studied the cosmic ray hypothesis, told Ars that the idea that cosmic rays would mainly affect the tropics was problematic. “[T]his seems to contradict our present understanding of the climate system. We believe that climate change is usually enhanced towards the poles.” While Muscheler thought the motivation for the study was reasonable, the results weren't a slam dunk. “I agree that the climate system might react differently depending on the state of the climate system and depending on duration of the forcing,” he said. “However, it is a problem if one sometimes seems to see a correlation between [cosmic ray] flux and climate and sometimes it is absent.”

Jürg Beer of the Swiss Federal Institute of Aquatic Science and Technology (who, along with Muscheler, were part of the group that looked at the Laschamp event) also expressed skepticism to Ars. Beer argued that the Laschamp event was sufficiently long for a cosmic ray impact on climate to have appeared, yet there was nothing obvious in the record. Beer also cautioned that uncertainties in the type of climate reconstructions available from the Osaka Bay core make it difficult to draw firm conclusions.

While the correlations in the study don’t seem to support the notion that cosmic rays are the primary drivers of climate change, as Henrik Svensmark originally hypothesized, there’s enough there to help sustain interest in the general idea. But finding erratic correlations can only get you so far, while demonstrating a valid mechanism by which cosmic rays would influence climate would go a long way toward validating the hypothesis.

43 Reader Comments

"Some of that attention comes from folks desperate to find a climate control knob that makes anthropogenic greenhouse gas emissions seem insignificant..."

That seems a little unnecessary to me. I guess you could have also said, "While some of the skepticism of the cosmic-ray climate theory comes from those who want the climate control knob that makes anthropogenic greenhouse gas emissions seem more significant"

Either way, I don't think it helps that much in a Science story. I don't find the cosmic ray climate theory all that compelling (yet). But I don't see any reason why it should not be properly investigated.

"Some of that attention comes from folks desperate to find a climate control knob that makes anthropogenic greenhouse gas emissions seem insignificant..."

That seems a little unnecessary to me. I guess you could have also said, "While some of the skepticism of the cosmic-ray climate theory comes from those who want the climate control knob that makes anthropogenic greenhouse gas emissions seem more significant"

Either way, I don't think it helps that much in a Science story. I don't find the cosmic ray climate theory all that compelling (yet). But I don't see any reason why it should not be properly investigated.

--t

Eh, it is more of a comentary on people's motives than on the science, and I think it is reasonably stated as such. Anyway, I also kind of think that there's a bit more active 'desperate seeking' in the form of coming up with this theory and studying it than there is in looking at it skeptically. You have to admit, it is a pretty far-fetched theory. If you had to ask me which is FAR more likely to be a major climate factor just out of the blue without any prior context, CO2 in the air or cosmic rays, don't you think CO2 would be the far more obviously likely culprit? I don't think the cosmic ray theory should be dismissed out of hand, but given that nobody has found any real significant supporting evidence of any convincing sort I'd probably fund studies of other things.

This article specifically stated cosmic rays which were defined to be high energy particles from outside the solar system(like gamma rays from super novas). This is markedly different than solar weather. As the article also goes into detail, had you read it, the real question is if this has any significant impact on the climate. At this time the evidence seems inconclusive.

This article specifically stated cosmic rays which were defined to be high energy particles from outside the solar system(like gamma rays from super novas). This is markedly different than solar weather. As the article also goes into detail, had you read it, the real question is if this has any significant impact on the climate. At this time the evidence seems inconclusive.

The link is that solar weather has a strong effect on the cosmic ray environment for the Earth.

Quote:

In 1959, the late Edward Ney of the U. of Minnesota suggested that any climatic sensitivity to the density of tropospheric ions would immediately link solar activity to climate. This is because the solar wind modulates the flux of high energy particles coming from outside the solar system. These particles, the cosmic rays, are the dominant source of ionization in the troposphere. More specifically, a more active sun accelerates a stronger solar wind, which in turn implies that as cosmic rays diffuse from the outskirts of the solar system to its center, they lose more energy. Consequently, a lower tropospheric ionization rate results. Over the 11-yr solar cycle and the long term variations in solar activity, these variations correspond to typically a 10% change in this ionization rate. It now appears that there is a climatic variable sensitive to the amount of tropospheric ionization—Clouds.

BTW, the solar wind is still unusually weak, even though we're near the Cycle 24 solar maximum...and we're in a 15 year pause in statistically significant warming. Real cloud behavior and its effect on albedo is notoriously difficult to model.

To be fair, it wouldn't exactly be surprising if the environment our planet was located in impacted its climate. As several have noted, the work to date is inconclusive, but we don't even have a solid understanding of the impact local phenomenon have, let alone how relatively minor forces from outside our solar system might impact our climate models.

There was a recent article on Ars about how heat from cities/power plants, previously thought irrelevant, is now showing signs of relevance not because of the heat they add, but because of the heat they displace and the impact that displacement has on our global climate models. I don't think it's surprising they'd find some evidence of correlation between cosmic rays and climate because ultimately it's unlikely that it's not (at least) some small piece of the puzzle. Whether or not we can get reasonable accuracy in our climate models without accounting for cosmic rays is a separate question.

BTW, the solar wind is still unusually weak, even though we're near the Cycle 24 solar maximum...and we're in a 15 year pause in statistically significant warming. Real cloud behavior and its effect on albedo is notoriously difficult to model.

"Since clouds reflect sunlight back into space, more of them should mean a cooler climate (although that depends in part on the clouds' altitude)."

This blanket statement needs a further qualification - it also depends on the time of day: cloud cover at night has the opposite effect of increasing surface air temperatures as it acts as an insulating barrier, preventing radiation of heat back out into space. This is particularly noticeable during winter in the higher latitudes. So, no, more of them doesn't always mean cooler temperatures - it depends on when there are more of them and where.

I thought solar cycles were today's favorite natural cause for climate change? Have they gone out of fashion?

No. As I pointed out above there's a strong relationship between solar cycles, solar wind, and cosmic ray influx.

During strong solar maxima solar wind speeds are around 600 km/s. As of today (supposedly near the Cycle 24 maximum although I expect it won't occur for up to two more years) it's around 400 km/s, and has often recently been around 300 km/s.

BTW, the solar wind is still unusually weak, even though we're near the Cycle 24 solar maximum...and we're in a 15 year pause in statistically significant warming. Real cloud behavior and its effect on albedo is notoriously difficult to model.

Please see the first link in the 3rd paragraph.

Sure, indicating that there are other factors in play besides cosmic rays. I find that not at all surprising. The fact that so many physical effects are still poorly understood along with their interplay in a chaotic system is the exact source of my lack of faith in the fidelity of current climate models.

Still, the strong correlation in the earlier part of the record is striking.

No. How many times over how many years do I have to explain to you what statistical significance means? We have not reached a "pause in statistically significant warming" that's lasted for fifteen years. It means that 15 years is not long enough to reach a statistically significant conclusion whether it's warming or not. Not enough data to say. The fact that adding just a few more years to the record lets us draw a strong and statistically significant warming trend should tell you that the apparent lack of significance over 15 years means you're picking a time span that's too short to tell you anything, and that you're likely running into issues with end-point selection sensitivity instead of describing anything real in the climate system. Any claims of a "pause" are unfounded from the statistics. I've been plainly explaining this to you for years and you have zero excuse to keep bringing up the "pause since X" argument. Stop it.

If you want to assign influence from the sun's activity (whether tied to cosmic rays or not) over recent years, Foster and Rahmstorf (2011) and Rahmstorf, Foster, and Cazenave (2012) do a much better job of capturing its potential influence and comparing it to other factors like ENSO and volcanic activity. Their work does not support the strong correlation you want to insinuate.

This article specifically stated cosmic rays which were defined to be high energy particles from outside the solar system(like gamma rays from super novas). This is markedly different than solar weather. As the article also goes into detail, had you read it, the real question is if this has any significant impact on the climate. At this time the evidence seems inconclusive.

Actually no you are wrong. The conditions within our SOLAR system, which not only implies emissions from our sun but also includes any in coming radiation (cosmic rays) is in fact SOLAR, as in solar system, weather. Fact is just as we orbit the sun our solar system orbits the center of the galaxy. Our path takes us through areas of high radiation and other things which have a direct impact on conditions within our solar system. THAT is solar weather.

This article specifically stated cosmic rays which were defined to be high energy particles from outside the solar system(like gamma rays from super novas). This is markedly different than solar weather. As the article also goes into detail, had you read it, the real question is if this has any significant impact on the climate. At this time the evidence seems inconclusive.

Actually no you are wrong. The conditions within our SOLAR system, which not only implies emissions from our sun but also includes any in coming radiation (cosmic rays) is in fact SOLAR, as in solar system, weather.

I cannot find a definition for solar weather. Pretty sure you made it up. I can find a definition for space weather, which is largely driven by the solar winds that stream from the sun. What I got from this article is that they were studying cosmic rays which have much higher energies than what the solar winds produce.

This article specifically stated cosmic rays which were defined to be high energy particles from outside the solar system(like gamma rays from super novas). This is markedly different than solar weather. As the article also goes into detail, had you read it, the real question is if this has any significant impact on the climate. At this time the evidence seems inconclusive.

Actually no you are wrong. The conditions within our SOLAR system, which not only implies emissions from our sun but also includes any in coming radiation (cosmic rays) is in fact SOLAR, as in solar system, weather.

I cannot find a definition for solar weather. Pretty sure you made it up. I can find a definition for space weather, which is largely driven by the solar winds that stream from the sun. What I got from this article is that they were studying cosmic rays which have much higher energies than what the solar winds produce.

BTW, the solar wind is still unusually weak, even though we're near the Cycle 24 solar maximum...and we're in a 15 year pause in statistically significant warming. Real cloud behavior and its effect on albedo is notoriously difficult to model.

Agreed, although as an aside one might also observe that 2009, the "hottest year recorded", coincided with the lowest solar activity (and insolation) recorded as well, which pretty much puts the kabosh on the whole thing.

Sure it does. There is also minor correlation both with how one chooses one's statistics, and their significance. As in "I cherry-picked both my dataset and the starting point of my time sequence to confirm my bias that there's been no 'statistically significant global warming' since 1998".

Seriously. Just choose HadCRUT3 for your surface dataset, which is known tounder-represent the polar regions that have seen most surface warming of this century, start your time sequence at the warm year 1998 which by utter coincidence also coincided with the strongest (by MEI) El-Nino of that century, and conclude that global warming is history.

Or hysteria. Its proved either way.

Now ENSO is just one of several quasi-cyclic mechanisms by which the oceans exchange heat with the atmosphere. There's also teh Pacific Multi-Decadal Oscillation and teh North Atlantic Oscillation (if that's what it is) and God knows -- Posieden in this case -- what else 'cuz I'm not an oceanographer. But whatever they are, they can operate in phase and out of phase and everything in between on time scales of over a decade, which is why IPCC chooses a long-running ten-year binomial filter to smooth their official surface temperature series. And they combine all three datasets, GISTEMP, NCDC, and HadCRUT, to estimate their surface temperatures. And then they do not conclude that surface temperature accurately represents global warming 'cuz size (and heat capacity) do matter and the oceans do absorb some 90% of the planet's heat imbalance, and ocean temperatures down to at least moderate depth keep on going up like clockwork.

But we can neglect all that because we're landlubbers, homo sapiens sapiens (allegedly) fer chrissake, not, ah, fish.

No. How many times over how many years do I have to explain to you what statistical significance means? We have not reached a "pause in statistically significant warming" that's lasted for fifteen years. It means that 15 years is not long enough to reach a statistically significant conclusion whether it's warming or not. Not enough data to say.

You can assert statistical significance over any interval. There is a question of whether the effect being seen is in fact a long-term effect. For instance, if the long-term solar output suddently increased by 2%, we would see a short-term statistically significant temperature increase, which would eventually be confirmed as a long-term trend.

At any rate, you can argue with the climate change skeptics at NOAA (see page 23):

Quote:

The simulations rule out (at the 95% level) zero trends for intervals of 15 yr or more, suggesting that an observed absence of warming of this duration is needed to create a discrepancy with the expected present-day warming rate.

I have reasonable confidence that global temperatures will drop as we head into the long and very quiet Solar Cycle 24 minimum after 2014 or so. If things evolve that way, I expect rather a few Arsians will be eating crow...or searching for yet another spin. ;-)

At any rate, you can argue with the climate change skeptics at NOAA (see page 23):

Quote:

The simulations rule out (at the 95% level) zero trends for intervals of 15 yr or more, suggesting that an observed absence of warming of this duration is needed to create a discrepancy with the expected present-day warming rate.

I have reasonable confidence that global temperatures will drop as we head into the long and very quiet Solar Cycle 24 minimum after 2014 or so. If things evolve that way, I expect rather a few Arsians will be eating crow...or searching for yet another spin. ;-)

Fascinating, Captain. You may expect what you wish of course, but one might note the authors of your cited NOAA reference (page 24) expect just the opposite:

Quote:

Given the likelihood that internal variability contributed to the slowing of global temperature rise in the last decade, we expect that warming will resume in the next few years, consistent with predictions from near-term climate forecasts (Smith et al. 2007; Haines et al. 2009).

I have reasonable confidence that global temperatures will drop as we head into the long and very quiet Solar Cycle 24 minimum after 2014 or so. If things evolve that way, I expect rather a few Arsians will be eating crow...or searching for yet another spin. ;-)

You can assert statistical significance over any interval. There is a question of whether the effect being seen is in fact a long-term effect.

If there is no statistically significant conclusion in the data you're looking at, you cannot call it a pause. You can only say that the data you have is not sufficient to establish either continued warming, zero trend, or cooling; the data would be consistent with all three mutually-exclusive scenarios. Calling it a "pause" means you have determined that one of the scenarios is correct, which you cannot do with so little data because the error bars are too large and can fit the other two conclusions in just as easily. That's what you're dealing with in the time period you've chosen. Stop calling it a "pause," because you have no basis for it with so little raw data.

If you want to call it a "pause" you have to show that the trend in the data really is flat and could not be construed as warming. You can't do that with the data we have over your chosen time period. You cannot confidently state that warming stopped because the data is consistent with continued warming (or cooling, or no trend at all). You have to have a statistically significant conclusion to identify a "pause." You don't have a statistically significant conclusion. This is not hard to understand.

If you want to examine any actual physical basis behind recent climate (like the influence of solar output or cosmic rays), looking at too few years to draw a conclusion of warming, cooling, or zero slope is not going to do it. You're also ignoring other well-known factors like ENSO and volcanic eruptions, which according to other researchers are conspiring to produce a cooling effect over the last several years. When they quantified the most likely physical factors working on the climate over short periods of time, it was found that ENSO had the greatest effect while solar variations had the smallest. When the quantified effects were accounted for, the "pause" you're referring to (or lack of statistically significant trend either way disappeared from the temperature records. With the confounding factors identify, quantified, and accounted for, you can also start to examine shorter periods of data for statistically significant trends. Low and behold, the last 15 years of adjusted data yields a statistically significant warming trend at a non-zero rate (with the possibility for a very large rate within the 95% confidence level). All five of the data sets examined show statistically significant warming since at least the year 2000.If you want to talk about very short periods of noisy data with lots of factors at play, this is the right way to do it. You're doing it wrong.

Quote:

At any rate, you can argue with the climate change skeptics at NOAA (see page 23):

Quote:

The simulations rule out (at the 95% level) zero trends for intervals of 15 yr or more, suggesting that an observed absence of warming of this duration is needed to create a discrepancy with the expected present-day warming rate.

At any rate, you can argue with the climate change skeptics at NOAA (see page 23):

Quote:

The simulations rule out (at the 95% level) zero trends for intervals of 15 yr or more, suggesting that an observed absence of warming of this duration is needed to create a discrepancy with the expected present-day warming rate.

Let me first point out that your source is from 2009, talking about the climate in 2008. With that in mind, let me point out that the quote you cherry-picked is from a block titled "Do global temperature trends over the last decade falsify climate predictions?" Their conclusion is, just shockingly, no. The last paragraph of that very section, with my bold, is:

Quote:

These results show that climate models possess internal mechanisms of variability capable of reproducing the current slowdown in global temperature rise. Other factors, such as data biases and the effect of the solar cycle (Haigh 2003), may also have contributed, although these results show that it is not essential to invoke these explanations. The simulations also produce an average increase of 2.0°C in twenty-first century global temperature, demonstrating that recent observational trends are not sufficient to discount predictions of substantial climate change and its significant and widespread impacts. Given the likelihood that internal variability contributed to the slowing of global temperature rise in the last decade, we expect that warming will resume in the next few years, consistent with predictions from near-term climate forecasts (Smith et al. 2007; Haines et al. 2009). Improvements in such forecasts will give greater forewarning of future instances of temporary slowing and acceleration of global temperature rise, as predicted to occur in IPCC AR4 projections (Easterling and Wehner 2009).

That entire block is about how a slow-down in temperature rise around 2008 does not imply global warming was not happening, because, when they used then-state-of-the-art climate models, they discovered that periods of around-and-up-to a decade of flat temperatures where common even given long-term warming, because the climate system is extremely variable. I am in awe of the level of intellectual dishonesty you have achieved by pulling one sentence out of a side-bar and using it to give the astoundingly false impression that the source you're citing says exactly the opposite of what they actually say.

So, pro-tip: if you're going to lie about the contents of a report, don't include a link to the report; someone just might check it.

For the record, I'll also include the very first sentence of the report you linked:

Quote:

2008 was cool, but only in the context of the last few very warm years. It still ranks within the 10 warmest years on record. The primary cause was a moderate to strong La Niña event.

So, according to NOAA, it's been getting hot, it's still really hot, and the slow-down was largely a temporary thing due to La Nina.

Of or relating to the sun, specifically. So one would quite naturally read "solar weather" as referring to the direct impact of (the radiation and particulate matter emitted by) the sun. Which by most reasonable interpretations would exclude extrasolar particulate radiation, i.e. cosmic rays.

Actually no you are wrong. The conditions within our SOLAR system, which not only implies emissions from our sun but also includes any in coming radiation (cosmic rays) is in fact SOLAR, as in solar system, weather.

I cannot find a definition for solar weather. Pretty sure you made it up. I can find a definition for space weather, which is largely driven by the solar winds that stream from the sun. What I got from this article is that they were studying cosmic rays which have much higher energies than what the solar winds produce.

Tell me what extrasolar is.

/face-palm

I am curious if you know where most gamma rays come from that hit the earth. Intra or extrasolar? Do you think its important to make a distinction between energy sources that are emitted from the local sun vs outside our solar system?

I feel like the questions you're asking could just be answered by actually reading the article. Why do papers tend to focus on one mechanism? Because they're trying to isolate it from the others and see what kind of effect it as (if any). That's important to know. Why did they check to make sure the periods with different magnetic field strengths showed a difference in climate? Because that's exactly the question they were trying to examine in detail; if there was no discernible difference then there's not much of a mechanism to explain in the first place.

Actually no you are wrong. The conditions within our SOLAR system, which not only implies emissions from our sun but also includes any in coming radiation (cosmic rays) is in fact SOLAR, as in solar system, weather.

I cannot find a definition for solar weather. Pretty sure you made it up. I can find a definition for space weather, which is largely driven by the solar winds that stream from the sun. What I got from this article is that they were studying cosmic rays which have much higher energies than what the solar winds produce.

Tell me what extrasolar is.

/face-palm

I am curious if you know where most gamma rays come from that hit the earth. Intra or extrasolar? Do you think its important to make a distinction between energy sources that are emitted from the local sun vs outside our solar system?

Again, we are talking about the conditions inside our solar system (weather) which is a mix of emissions from our own star and sources outside our solar system.

Anyone who has taken a cloud physics class knows this hypothesis is idiot to the extent that it posits "warm cloud" nucleation effects (liquid water droplet nucleation, which can in fact take place down to about -20 C, because of the paucity of ice nuclei. Below -20 C homogeneous ice nucleation [no nucleus needed] starts to be efficient)

Even in the cleanest most remote environments the atmosphere always has a reasonable supply of CCN, far larger numbers of CCN active at much lower supersaturations than cosmic rays can generate.

If this idea has any validity at all, it would be for high-altitude ice clouds, changing cirrus systematically. I am pretty damn skeptical, but won't yell "bullshit" too loudly. The burden is on those who advocate for this to come up with a mechanistic explanation which holds together. So far they haven't, and the stats look weak, to put it mildly.

BTW, the solar wind is still unusually weak, even though we're near the Cycle 24 solar maximum...and we're in a 15 year pause in statistically significant warming. Real cloud behavior and its effect on albedo is notoriously difficult to model.

I'm not sure what you mean by "statistically significant" (perhaps you could provide a more precise definition of what you mean) but I'm pretty sure that it doesn't mean what you intend it to mean.

As a sort of qualitative presentation of why we can't infer much of anything from a small segment of data subject to noise you might have a look at this plot:

Spoiler: show

The data (red) in this figure is the NCDC global temperature anomaly (I picked this data set for no particular reason... if you prefer another and post a link to the data I'll use it instead). Each point on the blue line is the slope of the least-squares fit of the anomaly data for the 15 years proceeding and including that year (in degrees C/decade). The green line is the least-squares fit for the entirety of the anomaly data. As you can see (blue line), although less than it has been recently, the 15-year-fit slope for this year is still positive, but as you can also see there have been periods in the past when the slope was zero or less. But the overall fit over the entire period of the anomaly data (green line) is positive slope.

TLDR: You simply cannot conclude anything about overall trend by looking at a 15 year period of temperature data.

I am pretty darn sceptical... The burden is on those who advocate for this to come up with a mechanistic explanation which holds together. So far they haven't, and the stats look weak, to put it mildly.

Well shit yes, Bad One. But they have to look, otherwise the denialists will claim the climatologists aren't doing their job.

It seems from the article that these scientists aren't taking into account the possibility that there may be multiple factors at play at any moment, some of which may still be unknown to us, and that the correlation exist when these factors line up together, and disappears when they oppose each other and cancel each other out.

You can assert statistical significance over any interval. There is a question of whether the effect being seen is in fact a long-term effect.

If there is no statistically significant conclusion in the data you're looking at, you cannot call it a pause. You can only say that the data you have is not sufficient to establish either continued warming, zero trend, or cooling; the data would be consistent with all three mutually-exclusive scenarios. Calling it a "pause" means you have determined that one of the scenarios is correct, which you cannot do with so little data because the error bars are too large and can fit the other two conclusions in just as easily. That's what you're dealing with in the time period you've chosen. Stop calling it a "pause," because you have no basis for it with so little raw data.

I guess you're going to have to argue with one of your favorite people, Phil Jones:

Quote:

B - Do you agree that from 1995 to the present there has been no statistically-significant global warming?

Yes, but only just. I also calculated the trend for the period 1995 to 2009. This trend (0.12C per decade) is positive, but not significant at the 95% significance level. The positive trend is quite close to the significance level. Achieving statistical significance in scientific terms is much more likely for longer periods, and much less likely for shorter periods.

If you want to call it a "pause" you have to show that the trend in the data really is flat and could not be construed as warming. You can't do that with the data we have over your chosen time period. You cannot confidently state that warming stopped because the data is consistent with continued warming (or cooling, or no trend at all). You have to have a statistically significant conclusion to identify a "pause." You don't have a statistically significant conclusion. This is not hard to understand.

If you want to examine any actual physical basis behind recent climate (like the influence of solar output or cosmic rays), looking at too few years to draw a conclusion of warming, cooling, or zero slope is not going to do it. You're also ignoring other well-known factors like ENSO and volcanic eruptions, which according to other researchers are conspiring to produce a cooling effect over the last several years. When they quantified the most likely physical factors working on the climate over short periods of time, it was found that ENSO had the greatest effect while solar variations had the smallest. When the quantified effects were accounted for, the "pause" you're referring to (or lack of statistically significant trend either way disappeared from the temperature records. With the confounding factors identify, quantified, and accounted for, you can also start to examine shorter periods of data for statistically significant trends. Low and behold, the last 15 years of adjusted data yields a statistically significant warming trend at a non-zero rate (with the possibility for a very large rate within the 95% confidence level). All five of the data sets examined show statistically significant warming since at least the year 2000.If you want to talk about very short periods of noisy data with lots of factors at play, this is the right way to do it. You're doing it wrong.

You're of course making the assumption that a) the data being examined was sufficiently accurate and b) all of the relevant physical processes are correctly modeled and accounted. I'm not willing to make those assumptions without a lot more investigation.

Quote:

At any rate, you can argue with the climate change skeptics at NOAA (see page 23):

Quote:

The simulations rule out (at the 95% level) zero trends for intervals of 15 yr or more, suggesting that an observed absence of warming of this duration is needed to create a discrepancy with the expected present-day warming rate.

It's been 17 years since 1995, and temperatures haven't increased recently. Regardless of the "statistical significance" of the results, it certainly isn't positive for the AGW hypothesis that warming is so muted despite atmospheric CO2 levels being at an all-time high, and well above Hansen's danger threshold of 350 PPM. At any rate I'm more than willing to see how things go for the next few years - that should be definitive.

In case you've forgotten, I have no problem with reducing the use of CO2 generating fuels. The issue for me is that it's important to provide widely available cheap energy. To do that while cutting CO2 emissions will require a massive buildout of nuclear generation, along with possible future developments like cheap endpoint solar generation or LENR.

Wind generation should be thrown in the dustbin of failed ideas, as this cautionary tale points out: Wind turbine collapses in high wind. I wonder what the payback period would have been for this peak 50 KW wind generator that cost around $390,000...

With no meaningful mitigations in sight, you'd better hope climactic CO2 sensitivity is lower than you think it is, or that other influences reduce global temperatures.

I literally cannot believe you're STILL clinging to the Phil Jones thing after I've already explained that one to you several times over the years. Like here. It was out of date when you got it wrong two years ago and it's even more out of date now.

I literally cannot believe you're STILL clinging to the Phil Jones thing after I've already explained that one to you several times over the years. Like here. It was out of date when you got it wrong two years ago and it's even more out of date now.

How fucking stupid can you be?

Fine, I see that Jones has since declared there to have been "statistically significant" warming since 1995. Sorry, I had honestly forgotten that.

So, why don't you share your scenario for saving the world? Or are we all just dooooomed? lol

Like here. It was out of date when you got it wrong two years ago and it's even more out of date now.

How fucking stupid can you be?

I dunno, what I see are a bunch of facts mixed in with a bunch of angry ranting.* Anyway, there's lots of discussion in that same thread about other wrong stuff which we're still hearing about, too... Maybe if you tried summarizing without swearing, you could put the Phil Jones thing to rest this time around.

*) Not all of the facts there are correct, either. For example:

Wheels Of Confusion wrote:

ai33806 wrote:

There was not a statistically significant warming trend between 1998 and 2010.

It's not statistically significant because the time period is too fucking short.

I literally cannot believe you're STILL clinging to the Phil Jones thing after I've already explained that one to you several times over the years. Like here. It was out of date when you got it wrong two years ago and it's even more out of date now.

How fucking stupid can you be?

Fine, I see that Jones has since declared there to have been "statistically significant" warming since 1995. Sorry, I had honestly forgotten that.

So, why don't you share your scenario for saving the world? Or are we all just dooooomed? lol

The United States has no such scenario. According to Rep. Henry Waxman (D Ca) in remarks at Sen. Boxer's Environment and Public Works Committee briefing on climate science yesterday (Feb 14), it is unlikely we will have one in the foreseeable future. Rep. Waxman commended the professional panel Sen Boxer had assembled, and commended Sen. Boxer for having done so. Waxman informed that he had repeatedly tried to convene such hearings or briefings before the House Energy and Commerce Committee, but all such efforts to bring such credible scientific testimony had been rejected by committee leadership, their basic contention being the 2% reduction the U.S. has attained thus far is good enough and don't confuse us with the facts.

That doesn't mean that other nations with the foresight of a blind bat have not developed such scenarios. The U.K. is one. Their plans are outlined at https://www.gov.uk/government/publications/the-carbon-plan-reducing-greenhouse-gas-emissions--2, to give you some idea of what such plans might look like. Although currently well under way, they outline several differing strategies to attain their ultimate 80% reduction goal by 2060. They need to give several, as the final buy-in to the amount of nuclear realistically required must be made by our kids, and meantime the government needs to present WWS alternatives for the rainbows-and-unicorns greenies who are actually flogging/politically supporting climate change minimization and mitigation today, when it simply *must* get started.

Make no joke: the future of the planet and likely our species rides on the Green Movement today. You and I might argue that huge Nuclear R&D and Deployment are absolutely essential, but it will require major political support, and if we don't argue respectfully it won't happen.

Additional commentary at Report calls for huge expansion of experimental nuclear plants. Major background material by one of the report's authors, Prof. David MacKay, is at Sustainable Energy Without The Hot Air. Please note that Prof. MacKay's low opinion of hydrogen fuel cell cars has moderated considerably since 2009. I've kicking around a Wellhead-to-Wheels study commissioned by GM a while back indicating hfc to be energy-competitive with diesel even when the hydrogen is extracted from ng or fuel oil using conventional fossil fuel process heat where you've a shot at CCS. (Process heat from an MSR would be even better.)

In the EPW briefing video I was struck by the pleas to us, from Rep. Waxman and Senators Udall and Whitehouse both for active political support for their (as it turns out) extensive and exhaustive efforts to get this ball rolling in the U.S., and for ideas about how to better educate the rest of the public about the seriousness of the situation. Above all by their intelligence, and that of Senators Saunders and Boxer. These guys really do get it. The video is well worth watching. It puts very human faces and voices on those we might otherwise dismiss as "just another mindless politician." These ones aren't.

And what of you, mr. ai-somethingmeaningless? Everyone makes mistakes. Especially me. You've a head on your shoulders. Seriously, what are you going to use it for?

So, why don't you share your scenario for saving the world? Or are we all just dooooomed? lol

I'm with AI, if you can't propose a solution to the problem, the problem doesn't exist.

That's how I know that the sun will never supernova, and the heat death of the Universe is bs. I've also noticed that there are no more murders, rape, or other crime, because those are complicated problems with no simple solution, and hence fictional.

So, why don't you share your scenario for saving the world? Or are we all just dooooomed? lol

I'm with AI, if you can't propose a solution to the problem, the problem doesn't exist.

That's how I know that the sun will never supernova, and the heat death of the Universe is bs. I've also noticed that there are no more murders, rape, or other crime, because those are complicated problems with no simple solution, and hence fictional.

Er, Yonder, in fact the Sun will never supernova. I hope that sets your mind at ease. The heat death of the Universe is inevitable, are you suggesting that AGW is as well? I don't get your point.

As to murders, rape and other crime, I expect they will continue to happen, but they aren't an existential threat to humanity. According to the AGW alarmists, AGW is. You are also committing a non-sequitor in saying that they, or AGW, are fictional. The issues at hand are whether AGW is in fact a problem, or an minor effect for better or worse, and secondly whether other factors swamp the "anthropogenic" part...